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A hawk in pigeon’s clothing

I saw a Cooper’s Hawk catch a Rock Pigeon a few days ago. By itself that experience is noteworthy – a Rock Pigeon is a big bird for a Cooper’s Hawk to handle – but more remarkable was the way the attack unfolded.

Cooper’s Hawk, original acrylic painting copyright David Sibley

I was just finishing a birding walk at a local farm. Ahead of me was a small field, recently plowed, where twenty or so Rock Pigeons were foraging on the ground. Another bird was about ten feet up and flying across the field toward the flock. I didn’t give it much thought. It was just another pigeon making the sort of relaxed, floating approach that pigeons do – or so I thought. Except that when this “pigeon” got within about five feet of the pigeons on the ground it suddenly transformed into a Cooper’s Hawk!

The pigeons all burst into flight, but much too late. The hawk was already among them and knocked one out of the air in a cloud of feathers.

I was stunned. It’s always shocking to witness a life-and-death drama like that, but a few seconds earlier I was simply seeing a pigeon flying in to join the flock when suddenly everything changed. And I wondered: How could I (and, more amazingly, a whole flock of pigeons) misidentify a Cooper’s Hawk like that? The hawk was in plain view, flying over an open field. Admittedly I did not give it much attention in that first glance, but there was nothing that drew my attention. It “registered” as a pigeon, which made sense for a bird coasting across the field. The pigeons must have seen it the same way, because normally they would not just sit on the ground and allow a Cooper’s Hawk to fly into their midst.

I considered the possibility that this was just a very lucky Cooper’s Hawk taking advantage of an opportunity with a flock of pigeons that either didn’t see it or didn’t think it was a threat. But I can’t imagine a whole flock of pigeons not seeing this bird approaching, nor letting it get that close under any circumstances.

I think the most plausible explanation is that the pigeons saw the bird but didn’t recognize it as a hawk (the same thing that happened to me), and that this was due to some deliberate mimicry by the Cooper’s Hawk, a brilliant bit of acting.

Predators rely on surprise, so if there is any way they can camouflage or “disguise” themselves and sneak up on their prey, it makes sense that they would take advantage of that. The resemblance of Zone-tailed Hawk to Turkey Vulture is often cited as an example of this aggressive mimicry. Potential prey species don’t react to the common and benign presence of Turkey Vultures overhead, and a Zone-tailed Hawk can hide among the vultures and drop onto unsuspecting prey.

Zone-tailed Hawks are born looking like Turkey Vultures, and they take advantage of it. I believe this Cooper’s Hawk was doing something more deliberate and active, transforming its wingbeats and flight actions to mimic another bird.

I’ve seen raptors mimic the flight style of other species before. Several times at Cape May, New Jersey I saw Merlins adopt the undulating flight style of a Northern Flicker, or the irregular flicking wingbeats of a Mourning Dove. It was only for a second or two and always when they were low and actively hunting.

This behavior is so infrequent, and so brief, that I suspect it will be very hard to confirm that it is deliberate aggressive mimicry, but I believe that all of these predators are trying to disguise themselves in order to sneak up on their prey.

Comments

Thank you for sharing.
I have seen snowy egrets “act” liker forster terns
hovering a foot or so above the water , trying to feed
on the bait fish at the Bolsa Chica wetlands, Huntington Beach Ca,
I hadn,t seen that prior to last year.

I once saw a Sharpie use similar deception in my back yard. It sort of tumbled along the ground like leaves being rolled by the wind. In fact thats what I thought it was, leaves or a piece of paper. But as soon as it got close to a group of Juncos it turned into a Sharpie and grabbed one.

Working in Worcester MA, I generally see a few raptor vs pigeon chases each Fall and several weeks ago noted a flock of pigeons acting as if there was a predator near by. Scanning the flock for about 10 seconds I couldn’t find the culprit until one of the ‘pigeons’ turned out to be a Merlin, broke formation and unsuccessfully dove at a pigeon underneath it.

There were several factors at play here that could easily explain it – I was at a stop light and that was my main focus or I simply may have just not seen the Merlin. But it was a relatively small flock of pigeons fairly close to the car and scanning primarily for a different flight it blended right in with the pigeons.

This was the first time I had noticed a Merlin going after pigeons from ‘inside’ the flock as it seemed to be flying in unison among them.

There’s probably enough anecdotal evidence to support the idea that accipiters have learned to flush feeder birds into windows that it isn’t too much of a stretch to think that an accipiter has learned to capture prey in a more open environment.

Very interesting article! Certainly something to watch for in the future. I was also interested in your first comment about a rock pigeon being a large prey item for a Cooper’s hawk. I had thought so as well, however, at a banding station where I work, we regularly capture sharp-shinned hawks on a trap meant for goshawks that is baited with live rock pigeons (who are not injured in the process). The first time, I was rather astounded as the pigeon outweighed the hawk by a substantial margin, but it has become a somewhat regular occurrence. Sometimes we even capture the smaller males. Perhaps they only try for our pigeons because they recognize somehow that the pigeons can’t fly away, but It really causes one to wonder if large prey items are consumed by small accipiters more often than we realize!

David what a great experience! It makes me ponder the colloquial names of raptors: chicken hawk, sparrow hawk, and pigeon hawk. I was doing some fieldwork a few years back and witnessed a red-tailed hawk running around on the ground just like a chicken. I supposed it was chasing a small mouse or a large insect. It was comical to watch.

I have a photo of a flock of vultures above my house in Lake Placid, FL. What prompted the photo was the bird on the left side of the flock wasn’t a vulture. It turned out to be a red-tailed hawk. When I zoomed in on the photo, I could see that the hawk was intently scanning the ground, appearing to be hunting. I’ve watched the vultures above the house and noticed that birds on the ground don’t seem respond to their presence, so the hawk seemed to be taking advantage of this by hiding in plain site.

It wasn’t a case of mimicry, but one of those magic moments that occur inexplicably, when a startled male Kestrel dropped a just killed White-throated Sparrow at my feet. It was such an unexpectedly unique occurrence that I was left wondering if it weren’t some sort of sign from on high. I suppose it wasn’t, but it was wonderfully memorable just the same.

Several years ago I was birding at the top of the ridge above our Kentucky farm at dawn. I noticed as the sun rose, an American Kestrel roosting in the bare branches of a tree, other nearby branches were filled with sleeping birds as well, including Flickers.

They all woke, stretched, preened, then eventually flew off..the Flickers to hunt ants in the fields and the Kestrel to some trees across the field. After a bit, I heard the “KIK-KIK-KIK” of a hunting Kestrel as it returned with its mate.
The other birds dove for cover or froze, but the Kestrel suddenly dropped into the grass and pounced on a Flicker the same size or larger than it was.
They briefly tore around the field close to the grass, but the Kestrel pulled it down and killed it. I couldn’t believe my eyes…they’d just been roosting together!

It reminded me of those old Coyote versus the Sheepdog cartoons, where the predator and prey eat lunch together, clock into “work,” then go into attack mode.

Recently I saw a Cooper’s Hawk stalking a varied thrush. Several times, the hawk made soft peeping noises, similar to the sounds a small bird might make when there is no danger near. Is this, perhaps, a form of deception? (Also interesting, to me, was the behavior of the thrush–which was not fooled and managed to escape, partly because I stumbled upon the scene…) This occurred at the edge of a parking lot near a large city park in Bellingham, WA. Here is the description I put on my Facebook page:
“At the edge of the parking lot I happened to see a varied thrush sitting on a bare branch about five feet off the ground. Nothing odd about that–except this bird was absolutely motionless. It looked like a wood carving. Not a twitch. I watched for a minute or two, wondering what was going on. Then I saw a larger, dark shape on another branch about eight feet farther up the tree. A Cooper’s hawk. The hawk was peering in the general direction of the thrush but did not seem to be able to see it when it wasn’t moving, even though it was in an exposed position. After another minute the hawk moved to an adjacent doug fir and sat there for awhile, still keeping watch and making small peeping noises at times as if to impersonate some harmless songbird. Eventually the hawk gave up and flew off, and that brought the paralyzed thrush back to life.”

The Cooper’s Hawk(s) that hang around our house have a neat trick too. The little birds try to hide in our fire bush, but the hawk stalks around on the ground, looking up from under the bush until it see’s an opportunity, then leaps up into the bush. More often than not they ar rewarded with a meal.

That is common sharp shinned Hawk behavior, as well. I found that out while trying to ID a predator rummaging around in the bushes in PA. I thought it was injured and went nearer but it exploded out of the bushes. i managed to get a photo because I had the camera out as I approached but couldnt positively identify from that quick shot. Further research proved , from behavior , that it was a sharp shinned, who has earned the name Bushwacker from its habit of beating the bushes looking for small birds .

I have witnessed the exact same thing several times in late summer when a lot of killdeer YOY were first learning to fly. The cooper’s comes in at about my head height [~ 1 meter] and flies right over the parking lot where all the killdeer are. The experienced killdeer instantly crouch down and freeze but invariably there’d be that one youngster that panics and tries to bolt, getting hit exactly as you describe the pigeon.

I believe it is just meant to be a sneak attack that does not give the target time to decide if the oncoming bird is a threat. Only one in the flock needs to panic and bolt.
You can maybe see comparative behavior from airplane pilots in war time who fly close to the ground to sneak up on ground targets.

Every year, in the fall, for the past 12 years, I have had a front row seat to the characteristics of a Cooper Hawk that frequents our “birdie banquet table” or, better known as, our bird feeders. There we see daily the unique methods he uses to catch his prey. From diving full bodied into the large Fir trees we have on our property and scattering 30 birds that literally explode from the tree, to seeing him run around the base of the tree on the ground doing his best to catch a unaware bird. Even to flying in low, like a super sonic jet, and skimming our roof top to try and use his “stealth attack” mode on them. He does manage to capture the more large bodied birds,like the Doves, who have a slower take off then other smaller birds, more regularly. But I have never seen him use the techniques you have just explained. But from now on I will be more alert to any new tactics he comes up with. 😉 At first this “circle of life” moments were upsetting and I would chase him away. Then I quickly realized that he needed to eat too. Either way it is fascinating to watch.

I studied band-tailed pigeons for years and saw this behavior first hand. The hawk mimics the flight pattern of the pigeon and when within 5 feet or so they strike. In addition to size, beak color, leg color, and banding on the tail of these two species are also quite similar.

I along with the rest of the family are very familiar with Mr. Cooper. I use to have homing pigeons. I tried to have special event birds, ( Weddings, Grand Openings, Sporting events, etc.)Anyway, that business didn’t work out so well. Once the Coopers Hawks found out where the coop was, It was all over. In just a couple of years, I lost 15-20 birds! They usually take down the pigeon and eat just the whole head and neck?. They leave the rest of the carcass!.

I’m a falconer who has specialized in accipiters for over fifty years. I’ve seen a lot of these sneak attack methods over the years with both trained and wild hawks.

I was stopped at a red light in Aurora, Colorado one day when I saw what appeared to be a pigeon flutter down out of a tree to just below the tops of the cars on the other side of the road. It suddenly turned into a Cooper’s hawk that used the cars to hide it’s flight to the bushes across the road. It then flared up over the bushes and did a wingover, and a flock of pigeons took off; minus one of their number.

Interesting blog. I have become more aware of Cooper’s Hawks since they have been nesting in my neighborhood. I live in south Florida and according to some field guides, they aren’t supposed to be here all summer. I hope to observe the behavior you describe.

I’ve had cooper’s hawks in my back yard for many years. But this fall, I noticed a new behavior; one would fly in, scattering the feeding cardinals/jays/juncos, etc…and he would fly on past my yard. At which point ANOTHER cooper’s would fly in, grabbing one of the songbirds that had been hiding. Not sure if they’re siblings or a parent with a juvenile (they’re flying too fast for good ID). I never knew cooper’s were cooperative hunters, but I’ve seen them use this tactic several times. Also, has anyone else noticed that coops seem to hunt very much like cheetahs do? They literally wear their prey down, chasing up, down, in every direction. Then, I’ve seen them literally reach out and “tag” their prey, (usually a cardinal in my yard) knocking it off balance just long enough to bring it down. Like Susan mentioned above, I used to interfere in these situations when I was rehabbing only songbirds…then, I became permitted to rehab birds of prey…..and I realize how very difficult it is for especially first year birds to survive. I no longer interfere…but I admit to turning away from my window once prey is firmly in grasp.

I had a similar experience this past month myself. I was watching a group of Rock Pigeons flying around above a river as if there was a predator around, but I couldn’t find one, so I got to meticulously counting the Pigeons in flight. Suddenly, materializing from within the group was a Cooper’s Hawk. I couldn’t believe how it had blended right in with the group, appearing just like the pigeons, flight pattern and all. It fell behind the group and quickly went on hot pursuit but failed to catch any of them and soon turned away in the opposite direction.

What’s interesting is that the group seemed to have been aware that there was danger nearby, but the accipiter was in the center of the group.

Perhaps this behavior came about as an extension of the Cooper’s Hawk’s unusual ‘moth flight’ display behavior that it exhibits (so I am told) for only a brief period during courtship. I have seen it and also seen excellent experienced birders puzzle over the hawk ID because it is so un-accipiter like. Perhaps while doing the courtship display, some Cooper’s hawks have caught on that this behavior is also a great way to snag prey as well as mates. Sue

OM Goodness so glad Laura published this on FB, I have pix of a juvenile Coopers in my yard a few days ago he was aggressively feeding on many different smaller birds…the time frame was about four hours I was so excited to have had the opportunity to have witnessed a Haw so close by.
This was a rare opportunity and I took pictures as close as I could get.
Thanks for you wonderful tale of this stealthy Hawk…………

Excellent stories. In response to David’s post, I have observed this behavior in Cooper’s in my south Florida neighborhood growng up. Adversely, we also observed doves behaving like hawks. No clue what the benefit of reciprocal mimicry might be. I now live in Missouri, but my grandmother back home in Miami has been reporting the hawk in her neighborhood (description only so unsure if sharpie or coops) behaving like a dove to get close to the rock pigeons as well. And in response to Cathy Ford, I had a pair of Cooper’s Hawks breeding for three years in my neighborhood in Kendall. I was unaware of the value in reporting that at the time.

I am sure this behaviour from accipiter is normal but just not observed much, when you look at the colours of the male Sparrowhawk and Merlin as well as other Hawks such as Cooper’s hawks, I don’t think it’s coincidental that they are roughly the same size and colour of pigeons, but a evolutionary adaptation to be able to blend in with the prey species as part of a hunting advantage, and they are well known for taking advantage of cover to get close to them including the use of man made features such as windows where the prey is spooked into flying into the glass and then easily picked up whilst stunned in the floor.

The comment about Red-tailed Hawks running around on the ground chasing, we also observe this in the UK and Europe with buteo sp, they regularly found feeding on the ground ether eating worms and insects, and sometimes lizards and rodents. But the attitude of corvirds is different to them when they are doing this, they will often be feeding in the same field and are not phased by the buzzards at all.

Just two days ago I witnessed a Cooper’s Hawk flying swiftly, quietly within three feet against neighborhood houses, bank and swoop between two homes to land in a locust tree. After a three minute surveilance a quick attack into a nearby Blue Spruce which flushed a pair of Mourning Doves. After a few minutes chase, one dove escaped. The thing that sticks in my memory is that I saw a Cooper’s just two days earlier perched on a nearby chimney just observing, perhaps put off by my attempts to capture an image, idk. I was struck by the fact that this second visit used a route that deliberately hid the hawk’s approach, whereas the first visit was pretty open and the resident doves fled succesfully. I suspect a return for the remaining dove and a squirrel that was also under observation on the previous visit. I can’t prove it was the same individual but the behaviours are curiously related.

If you have had a chane to fly Cooper’s of various ages and genders for numerous years (like Richard and I, while unknown to each other and is different parts of N.A.) it is not really surprising that they employ different strategies to survive. Hunting different species often calls for different strategies which often are unknown but to the ardent student. The same is often true of other raptors as well. I’m not convinenced the prey species is “unaware” of the hawk amoungst their flock but rather the prey realizes braking from that flock often presents an advantage the hawk has been waiting for. The special skills the accipiters bring to the party is the ability to accelerate and go up compared to many buteos and even falcons. I would suggest many of these “unusual” techniques are practised more by sub or adult members of the species rather than juvenile as there are some learned components to the strategies rather than simple hardwiring.

A very amusing technique I was saw employed by a young male I was flying was the use of ground running to attack very large domesticated chickens. The hawk would fly to the ground from a moderately placed tree limb in a forested area near the free ranging chicken’s coop. Once on the ground the hawk could be seen and heard (bells) running after and jumping up to bind to a hen’s head. The hens were a large breed of chicken likely outweighing the hawk at least 5 fold. Unsuccessful at breaking into the hen’s skull and being shaken off his “perch” the dance was restarted. The hawk was determined and eventually successful. There is a great deal of literature about the wonders of Cooper’s hawk behavior. Drownding prey is another interesting technique. So much to learn and so little time.

Philip: It is very common for Redtails, as juveniles especially, to be seen foraging for insects here in their native N.A.. Common yet surprising is the fact this is done in non-related broods (often in flocks of 6-8 hawks that I have observed)and with adults often feeding fledglings that are not their progeny. Of course we have species of buteos that exist primarily on insects not sharing the far greater variety of prey utilized by Redtails.

While this isn’t a raptor, I’ve twice witnessed titmice doing very convincing dead leaf impressions, fluttering to the ground in an extremely unbirdlike manner, just like a falling leaf, when a predator (I think it was me once and a hawk once) approached.

Walked into the backyard and just randomly moved toward the tree line behind the house. A Coop I did not see was apparently watching the area, so when two Mourning Dove spooked up and away from me the hawk came in. I heard a loud bang against the house. One of the doves had hit the wall and the hawk had it pinned up against a window, I watched as the hawk got a better grip in mid-air and then fly off with the dove.

For a week or so an Eastern Phoebe was perching on a bare metal pole on our deck, used for a hummingbird feeder. I was in the house and saw a large bird pass by a rear window then low over the deck and snatch the Phoebe right off the top of the pole. I think the hawk had seen the Phoebe and had come around the front and side of the house and then ambushed the smaller bird from behind. Clearly a Coop id as it flew off.

An apparent juvie Coop running back and forth for dozens of feet along a large fallen oak tree trunk, looking much like a small Velociraptor or other predatory dinosaur might.

Saw a Coop chasing a Mockingbird across the front yard. The Mocker dove into a large evergreen holly bush across the street. The Coop followed right behind, crashing into the bush. The bush jiggled and shook as both birds ran around inside, hopping I guess from branch to branch. The Mocker was shrieking up a storm. Suddenly the Mocker stopped hollering and dropped out of the bottom onto the ground. It then flew off fast and silent to another clump of shrubbery further across the yard. The hawk continued searching inside the holly bush, I could see branch ends moving up and down. I had walked closer to this bush and when I was 30 or 40 feet away I made a little ‘tskk tskk’ noise. The hawk erupted from the bush and I was literally eye to eye with that bird until with about ten feet left to go it realized I was too big to eat and it turned and flew off.

A friend of mine (Richard Tofflemire) told me a Cooper’s Hawk acting story that I now tell during my Hawks and Owls presentations. Richard was in a parking lot and saw a Mourning Dove sitting on a wire right out in the open. Then he saw another Mourning Dove flying towards the perched bird. As he was watching the flying Mourning Dove, he thought something wasn’t quite right about it. The perched Mourning Dove watched the flying dove come in to land beside it. As the flying bird put on the breaks and did the fluttery Mourning Dove wing beats to land beside the first Mourning Dove, it suddenly threw a foot out and grabbed the perched bird! It was actually a male Cooper’s Hawk. What’s neat about this observation is the fact that the Mourning Dove watched the bird approach it from a distance, just like in David’s observations with the pigeons. As well, the Coop didn’t change its flight style at the last minute to bash into the dove; it actually even mimicked the landing style so it could be as close to the dove as possible before it grabbed it. Hooray for accipiters! They are so great to watch.

David- I’m just re-reading your article. I could see how this could be mimicry. Interestingly (to me) – when I looked at your image, it reminded me instantly of a Passenger Pigeon, in the general distribution of colours

Earlier this year about 7 or 8 am I was watching crows and sparrows eating from the road here at the Berkeley (California) marina. I thought I saw another crow coming in to join the breakfast party, gliding in lazy, low and dark–a few inches off the ground, with no reaction from the gathered birds (or from me), at least none that I noticed, until the incoming bird “transformed” into a Cooper’s hawk, chased a crow off its perch on a low boulder by the side of the road, then swooped up to a perch in a pine tree a few feet away.

Not sure what (if anything) the hawk’s game plan was, but the transformation was the startling, amazing thing.

Now if I had a recording of this ‘transformation’ i could check how much of it was me and how much was the hawk. Could also check how ‘fooled’ the crows really were.

If I were the conjecturing type I might say that this Coop was mimicking a Crow landing glide because they often feed together with Sparrows here, who don’t react much to the comings and goings of the Crows.

Do Cooper’s Hawks skim the ground like that normally? In other hunting situations?

I think I just witnessed exactly what you described! I’m sitting in my back yard playing a game on my phone when I hear a rustling. I turn to see 2 doves coming in, followed by another louder rustling which I assume is another dove. It briefly lands on a branch but takes off. It’s then I notice the straight tail, and the slowly beating wings and realize that it’s not a dove. I don’t know what it was, but it was very close in size to the doves. It appeared light in color, and possibly had 2 or 3 bars on the tail. I think the doves remained unharmed!